Printing telegraph system



Oct. 11, 1932. A. E. HUNT ET AL 1,881,607

PRINTING TELEGRAPH SYSTEM Filed June 13. 1931 5457' u/ve' SLOW um? Z 'lNI/ENTORS HUNT q z x mya ATTORNEY Patented Get. 11, 1932 UNITED STATES PATENT OFFICE ARTHUR E. HUNT, OF BROOKLYN, NEW YORK, AND WILMARTH Y. LANG, OF TOWACO, NEW JERSEY; SAID HUNT ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK, AND SAID LANG ASSIGNOR TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK Application filed June 13,

This invention relates to printing telegraph systems and more particularly to monitoring equipment for such systems.

The invention is particularly applicable to telegraph systems in which series of impulses I are transmitted and received in their proper sequence and phase relation by means of signal distributing mechanisms of the start-stop type, and in whichit is desirable at intervals to monitor the systems from a point where many lines are present. a

- In its preferredform the invention is applicable to telegraph systems of the type which is frequently used r'or news distributionservice and which serves one ormore stations over asi-ngle line. The line is usually a two-wire line forming in'eflect a loop in which the stations are serially included through repeaters. The, distributors are'of the start-stop type adapted for isochronous operation of the various stations and, besides the series of. impulses require for the transmission of a symbol, two extra. impulses are required forstarting and .stoppingthe distributors for each symbol. The line is normally closed between symbols and an opening of the line causes all distributors to start off an'dicomplete one revolution for the reception of a symbol. 3o

In present day practice certain lines. in these systems are run at a higher signaling speed than other lines, the high speed lines beingde'signe'd for 368. symbols perminute and the low speed lines for 289 symbols per minute. It hasbeen the practice in the past to have a monitoring equipment which comprised a transmitter, arecorder and two distributor units. One distributor unit would operate at the higher speed, the other at the lower speed, and by placing one or the other in a mounting frame,connections would be 7 made to the. transmitter and recorder. The

different speeds.

interchange of the heavy distributor sets for use with lines of different speed was cumbersome and slow. I I

An objector the invention is to simplify the monitoring of a group of lines operated at Another object is to prevent mutilation of messages on telegraphlines during monitorrnnvrme TELEGRAPH SYSTEM 1931. Serial No. 544,056.

ing, when a change over from one operating speed to another of the monitoring set is made. v

Another object of the invention is to simplify the change over from one distributor set to another in a printing telegraph set adapted for signaling at two different speeds without the necessity of using duplicate transmitting and receiving equipment.

For the attainment of these objects the invention involves a telegraph station equipment, which may be a monitoring set, for insertion successively intoa plurality ofline or loop circuits some of which are operated at high speedand others at low speed, the equipment comprising a loop circuit and two separate power driven distributor sets each having a sending and a receiving face to which are connected a common signal trans mitter, a common recording device and a common set of relays for start-stop control and storing of signals. The circuit changes required for the switching of the loop circuit from one distributor set to the other are accomplished automatically in response to the manual operation of a two position switch. The circuit is so arranged that during a switch-over operation the loop circuit is kept closed over by-paths around the distributors.

Some of the advantages of such an arrangement over prior arrangements are that only a single telegraphing set composed of transmitter, receiver and control relays is required for the two distributors; that by a single throw of a switch the'starting and stopping of the two distributor drives and all other necessary circuit changes are automatically carried out; that there is no danger of mutilation ofmessages passing on the line by the switch-over operation; and that one distributor set maybe removed from the equipment without disabling the other or disturbing its operation. I

The arrangement in accordance with the invention may readily be extended to equip ments for three or more speeds.

In the following detailed description of a preferred embodiment of the inventiomreference will be made to the accompanying drawing which is a diagrammatic representaplugged into a; plurality offset and slow lines. w

In the drawing, jacks J 1 and J-Qare shown connected to a slow line L-l ands" fast line L2, reisp'ectiveljif Thejscks' may beiriiountedflonsf switchboard together with a lerge number of similar acks coi'mected to other slow and fast l nes. Each line may be assumed in efiechto'form a loop circuit such b as referred'to above, including two or 'more stations and it is normally closed through the springs of its corresponding 130k. 'It shouldbe understood-thatthe telegraph stations may be connectedthrpugh repeaters to the main line'end that repeaters may beinsertedetintervals 1n the main line'in a Wellknownmanner. it should also be'understood that themonitoring jacks be located at any-oral stat ons and 'st'intermediate repater stations, where" a plurality of lines would'be'presentfi The monitoring set comprises a; distributor' 'set D 1, of the-start-stop vtype, having a motor M1 and aseniding face SF-l end receiyin g' face B F-el mounted on a common shzift S-1",- Wh ch for simplicity is represented. by ai'dott'ed line}, The motor onthe distributor set 'D"l is controlled toruii the setat zispe'ed correspondi'ng to thespeed' oi operations per minute.

the slow lines, which is 289 operations per 'minute, The'monitoring set further comprises a similar start-stop distributorset 2'ha-v1ng,e'motor Mf2,i a sending face SF+2 aiidareceivingiace RF+2 mounted" v on the she-it S 12. ,The motorld'2.1s"con trolled to run the distributor ate speed corresponding to that ofthe fast 7 For the purpose of accurately adjusting the speed of'the motors-end to maintain the speed constant,"eech'motor isrproizi'ded with e governor'mech'anism G1' and Gfflyrespectii eiy -"whi'ch controls the Contact for regulzition' oi'zthe armature current to my the speed Within two narrow limitg i Own manner.

' ..,Eachfdistributoriace comp ses zt s'eries of gst-ationary contzic't ringssub ii ided into segments "inf various manners as shown in f the drawing. Associated With ezich disc router vtribiitor face by s'frictionfclutch (not s;

farce a; brush arm carrying- Wipers adapted .t'oybridge two adjacent contact rmgsJEa -ch arm is mounted for rotationoVer the'disattached to the distributor shaft; "and its frotation is prevented by a catch, Which resy be operated by its associated start 'm'eg vet to release the. erm'and permit its free rotation in .unison with 1 the distributor ash distribution of i series; of

senting al'sjunbol. The tonne! of the start magnet 1ssuch that after 'completiod 'o double throw switch lines; orfor 368- t for the crises repre-l- I M "tion, connecting battery and ground ,to' the controleonductors 2lend 2O respectively An revolutiom the brush arm will again be caught and held stationary awaiting a new ated'by the passing ofx perforolt-ed tape to set up contact combinations corresponding to the Various symbols to be transmitted;

The mgnitoring set also comprisesa record- 1 s r mg .oevice R similar to that disclosed in Patent 1,,1'28 422 cleted February 16, 1915.

' The transmitter'T and therecord'er R and their associatedrelays comprise a circuit; portion', shown inthe drawing below'the' dot and desh' liiies AA, whichfis required for the operation of asingle distributor set and which in accordance with the preferred form of the invention is made commonto the low speed distributor D'l and the 'higlrspeed distributor D 2 shownabove theline A-A. For the switching ifrom oneidistributor to the other of the commoncircuit, a two-pole sprovide'd Which connects e'currentsource' suchasa grounded betteryfto the control -linesj20,- 2i and 22 for the operation" of switching {relays 30,

: Further details of the circuit will'be 1m dersto'od from descriptionof-the operation 0f the systemsi l v i 7 Thecircuit is shown in the drawing in condition for monitoring on affsst line, and it Willbe assumed that it is desiredto monitor 1, on thefast1ine-L2. Plug-P will be inserted in the jabkJ-Q, Wherebythe'normally closed path for-the line L'2 over the springs of thejsck is opened and replaced by the closed loop; circuit iii the monitoring set iwithoutinterruption of the line, the contacts between the plug and: the jackbeingmade before the spring contact-1on1 the jack is opened. 'l he closed loop'circuit referred to may be traced follows: 'Fr'om thetip'of plug P, conductors 100 and @101, bridgedsegments 6 and 10 of'sendi ig'iiace SI 2, conductor 71 02, bridgedsegments-(i and 100i distributor face S1 E 1, conductor 103', windingaof line relay LR5'conductor1O4; tothe sleeve of plug P The line relay-LR is' 'thus included the line circuitLi2=fend wi l be operated endreleased in response to impulses on the line.

The switch 25 is showniin its upper posi- 7 resistances 45 and 46 7 two limits at which the and which'are fixed by adjustment of resist- -LR,rarmature of relay energizing circuit is thereby closed through the windings of relays and 41 in series and in the operated condition of these relays the following circuits are closed: Armature runsthe shaft S-2. The operation of armature 43-closes another ground path through to armature of motor M2, line;21 and battery. When the motor attainsja certain speed the governor G-2 opens its contact and thereby opens a short circuit for resistance 46, which then is added to the armature circuit and causes the motor to slow down until its speed is such that governor G-2 again closes its contact; the motor will continue to vary its speed between the governor operates,

ances 45 and 46 to besuch that'the average speed will condition the distributor set for 368 operations per minute.

The placing of battery on conductor 2l by switch 25 prepares an operating circuit for start magnet RS- -2 which will be completed whenever the line relay LR de-energizes. This circuit may be traced as follows From ground, back contact of line relay 31, bridged segments 11 and 12 of receiving face BI 2,

winding of start magnet RS 2 to line 21 and battery; the start magnet isenergized in this circuit and withdraws its catch, thereby releasing the brush arm on the receiving face RIP-2, which in turn makes one revolution at aspeed determined b the speed of the motor M2'; the arm is t en again held stationary bythe catchuntil released by an- I Other de-energization of the line relay LR.

After the reception of a few symbols from the line the distributor will fall into phase with the line. When this condition obtains, the starting of the receiving distributor and the monitoring recorder in response to a deenergization ofthe line relay willvbe in phase with the starting of all receiving faces included in the line L-2 and will be caused bythe start impulse from ai -transmitter: on the line. In the system described, the line loop is assumed to be normally closed be- T tween successive series of impulses representing successive symbols," and the sendlng of 'a newsymbol ispreceded by a start impulse during which the line' is opened at a transmitting station causing all line relays'in the line loop to release and thereby starting off all receiving distributors associated with the line relays in. the manner just described for the distributor RF-2. The start impulse is followed by a series offive impulses comprising different combinations of line openings and closures corresponding to different symbols; in the case of high speed lines, such as L'2, the impulses pass over the loop circuit with a rapidity determined by the high speed in connection with the segment :13 through 7 the wipers on the arm. The speed of motor M-2 being adjusted for operation with the fast line L-2, the brush arm will pass over segment 1 at the time when the first line signal passes through line relay LR and will pass the succeeding segments at such times as the succeeding signals pass through line relayLR.

Assuming that the first signal of a symbol being transmitted is represented by a close ofthe line, relay LRwill-be energized and by its armature connects ground over bridged segment l3,conductor lll to receiving mag net Its-1. which operates. Assuming next that the second signalgis an openof the-line, line relay LR de-energizes and removes ground from segment 13 with the result that no ground will be placed on segment 2 connected through-conductor 112 to receiving magnet Rfi2,,and this magnet consequently does not operate. The remaining three signals of thesymbol passing through relay LR similarly cause the operation or non-operation of receiving magnets 11-3, R4 and 11-5 over conductors 113, l14-and 115. The operation or non-operation of thereceiving magnets of the recording device R effect selections of operating mechanism in the recorder for the translation of the received series of signals into the corresponding symbol. Immediately before the completion of its revolution the brush arm of distributor RF-2 bridges contacts 14 and 15 and thereby closes a circuit frombattery through a magnet BM of the line L2. v It will nowbe assumed that the operator desires to transmitamessage over the line I L-2-at this time,forwhich purpose he may place a perforated tape containing his message in' the transmitter T. The transmitter comprises astepping magnet SM for advancing the tape each time a symbol has been transmitted over the loop. The transmitter also comprises. a series of transmitting contacts TC which in response to the perforations in the tape cause the operation of one or more storing relays individual to each transmitting contact. For the sake of simplicity only two storing relays 81 and 82 are shown in the drawing, having their righthand-operating windings connected to corresponding contacts TC. Such storing relays i as have been operated will lock themselves in 'operatedncondition and thuspermit a new I setting of thetransmitting contact TO to be made while the setting on. the storing relays isbeing'transmitted by the sending distribuleft-hand winding of start relay 51, switch 50,. bridged segments 16 and 17,

, relay 51 The operator now closes switch 50 whereby a circuit'is extended from ground through back contact of armature 32 on'relay 30 to battery,.causing to operate and closealocking circuit to f g'round through its right-hand winding 2 .overarmature 55'of'keyboard relay 54, arm: ature 58 of lockout relay-56, one or more of over-the sa-me'c'ircuit Relay 51 in'operating also closes two circuits to ground at itslefthand' armature 53,'one of Whichmay be traced th'e transmitting contacts TC' through corresponding operating'windings of thezstoring relays to battery. Assuming that the circuit for storing relay 81 is closed and the circuit forrelay- 82 is opened at the transmit-ting con-H tacts TC, relay 82' will remain de-energized and relay 81Will' be operated and close a locking circuit from battery thronghits left-hand winding and le ft han'darmature throughre lay 54' andarmature 57'ofrelay56 toground;

Relay 54 operates inthis locking circuit and '7 opens the operating circuit for thestoring relays at its armature 55. Theright-hand armature's of'all the storing relays are con- *nec'te'd over conductors-121, 122, 1-23,]12 and S ll-2, thereby opening the mainloop circuit ,which resultsin a start impulse being trans- 125 to correspondihg'segments 1,2, 3,4 and onthesendi-ng distributor SF-2 which consequently are connected to or disconnected from the conductor 100 of the main loo-p circuit in accordance with the setting of the stor ing relays;-

' r The other circuit closed "by th e operation of armature 53of relay 51 may be traced from ground through armature 53, armatur -e134 of relay 31; sending startmagnet SS-2 to battery' on line 21; Start magnet SS-2 oper-' ates and releases the brush arm, whichconse uently makes arevolution overthesending face SF-2 at a speed determined by the motor M2 and corresponding to the transmitting speed of the line Commencingits, tr'avel'the'brush arm removes its wipers fromfise'gment ear the sending face mitted over the line L2, causingitherelease OfaIllinerelayS' including line rel'ayLRof the monitoring set. The release of line relay LR starts the receiving catama an-'2,

i as described aboveandthe releaseof allline v I relays vincluding the line, ,L 2**similarlyj starts their corresponding' receiving distrib- -As the brush armfofsending distributor-Q SF12 subsequently passes overi'segments l," 2, 3, 4: and 5,:the 1oop circuit will be closed and opened I accordance with the setting "ofthe-storing relays 81, 32, eto., astollows:

Fromconductor 100,-:righthand armature of operated storing relaysi81, 82 etc segments 1, 2,etc.'and ring 10 ofsendingfaceSF2,

conductor 102, bridged SegmentsZG and 10 of sending face SF'-1, conductor 103, line relay LR to conductor 10 1;? Impulse's corresponding to'the s-ettingot the storing relays are thus transmitted over the line circuitL',-2

with the proper speed for correct reception n over the various receiving} distributors.

These impulses are alsov received overthe re- 'ceiving distributor ar -'2 of the monitoring set by the recorder Rfwhich produces va rec- 0rd of the transmitted'message. 1? Thus in accordance with the setting assumed above of the storing relays 81ai'id'82,etcz the loopfc'ir cuit will be closed while the brush arm asses" over segment 1 i causing the operation of recelv ng 'J111&gnt" R''1 *-and;- w1llbe opened whfie the brush arm passes over segment 2" causing the :receiying' =mag'net R2 tofr'em'ain de energized. vThe remain- 'ing magnets 13-3, l t-4 an'd R dare simi la-rly selected. {The loopicircuit 'is jagain closedwhen the brush-"arm ofdistributor SET-2 :reaches segment 6: on which a the arm comes-to a stop;

Thecontrol-relays 751*, 5 1" and 56 are provided for the purpose of preventing interference between successive series ,of impulses and "their operation" is controlled from" the sending distributor SF '2 finthe following manner, When the brush arin' leavesfse'g ment 16, the" operating; and holding circuits for relay "51 described above are openedand the' relay releases and-risiprevented fromset of perforations and for a new: setting of the transmitting contacts TC. which however has no effect upon, thestori ng relays, since the ground a armamre'se been removed by the releaseio'f relay 51' andfby the foperation' ofrrelay5 The release of relay 51 also remoyed the ground "at'armature-53 from the operating circuit forthe start magnet S8 2 thereby causingt-he catch to fall back into the path of the brush armlof distributor SF'-2.' Immediatel -before the completion of'its revolution the-brush arm passes over battery at armature .32, bridgedgsegments 1'? "and 19, operating winding of "relay 56'to ground, thereby temporarily operating relay 56 I which at its; armature .58 introduces another temporary breakin the'operating circuit for the storingorelaysfil, 82;,ietc.='The operation of armature 57 of. relayi56 remoyes aground fromf the locking circuit-ofthe stOr- I segment 19 andthereby' closes a 'circuit from' l ations described above are repeated in conon the transmitter T.

nection with the new contact combination It should be noted thatthe loop circuitthrough the monitoring set besides being closed over the path includingthe bridged segments 6 and 10 of the sending face SF-l is also closed over a by-path which extends over conductor 105, armature 33 of relay 30 and its normally closed contact and conductor 106; the loop-circuit isthus independent of the. bridging of contacts 6 and 10 on sendin-g face SF1 and the distributor D1 may be entirely'disconnected and removed from the circuit without disturbing the operation of the fast distributor 13-2.

If the operator, instead of plugging into attained between the receiving face RF1 and the line L1, messages will be received on the recording device R over the conductors 111, 112, 113, 114 and 115 in the same manner as described for the receiving face RF2.' 1

When now for the purpose of transmission, the operator closes switch 50, the operating circuit for relay 51 is excited from ground through its left-hand operating winding, switch 50, bridged segments 16 and 17 of the sending face SF1, front contact and armature 32 of relay 30 to battery, causing relay 51 to operate and lock over its armature 52. The ground at armature 53 also is extended over armature 3 1 and its front contact, through the start magnet SS-1 of distributo D -l to battery on line 22, whereby the brush arm of sending face SF1 is started off on a revolution. Segments 1, 2, 3, 4 and 5 of the sending face SF-l are connected over conductors 111, 112, 113, 114 and 115 to the right-hand. armatures of the storing relays 81,

82, etc. The further operation of the circuit for transmission of impulses over the line Ir1 is similar to that described above in connection with the transmission of impulses over the distributor D2 and line jack J2 as described above, had plugged L into .jackJ-l of the slow line L.1 with the switch 25 in its upper position for operation of the" fast distributor 'D 2,=the difference in speed of the line L1 and the distributor D2 would cause the receiving distributor RF.2 to operate in a jerky .manner and would prevent proper reception of signals by the recorder R.- .Observingthis, the operator will disconnect the distributor D-2 by throwing switch 25 to its lower position thereby connecting the slow distributor D1 for operation. r.

In. this position of the switch 25,. battery and ground are extended to lines 22 and 20 thereby causing the operation of switching relays 30 and 31in series and the release of switching relays 4:0 and 41. When battery is placed on line 22 the various circuits required for the operation of motor M1 are completed over the back contacts of relays 40 and 41, and the motor Ml is brought u to speed and is controlled by its governor 1 in a manner similar to that described above for p the motor M2. The governor G'1 is adjusted for speed variations such that the average speed of motor Ml will correspond to239 operations per minute of the distributor D1, which correspondsto the operating speed of the slow line L1.'

' When now the line relay LR de-energizes, ground is connected from its armature over armature 35 and its front contact, bridged segments 11 and 12 of receiving face RF1 start magnet RS-1 to battery on line 22 thereby starting the brush arm of the receiving face RF-l. As soon as isochronism is It may be noted that the main loop circuit of the monitoring set besides being closed over the path including bridged contacts 6 'and lO of sending face SF2 under these conditions is also closed over a multiple path including conductor 107, front contact and armature 33 of relay 30 and conductor 105. The opening of the loop circuit by the removal of distributor D-2 or by the accidental release of its brush arm consequently will not interfere with the transmission of signals by the distributor D-1.

I If now the plug P is plugged into another fast line, the difference in speed of the slow distributor D1 and the fast line would again prevent the proper reception of messages and cause the distributor to operate in a jerky manner. The operator in observing this condition would throw switch 25 to its upper position thereby associating the fast,

distributor with the fast line. i

It may be further noted that, due to the fact that the loop circuit of the monitoring set is completed in parallel paths through the bridged segments 6 and 10 of the distributor faces SF-l and SF2 and through the armature 33 of relay 30 and its associated contacts, the throwing of switch 25 from one position to another and the consequent switch ing of the armature 33 on relay 30 between conductors 106 and 107 has no effect upon the loop circuit and consequently in no way interferes with the messages on the line.

The system described above is a preferred form of the invention and may be modified in various ways without a departure from the scope a the swash. Thus,the distributors-maybe duplicates and run at the same priate and 'other types .of distributors than that speed;the number of distributors may be.

greater than two; the distributors may be driven through magnetic-clutches and appro gearing from common driving means;

shown maybe used, as foreXample, the oscilhigh and low speed signaling,

latingtype or the continuously rotating type used in: full duplex telegraph What is claimed is: V

1; Ina signaling system systems;

a telegraph station comprising a line circuit, a high speed signal distributing device, a low speed signal distributing device, a common telegraphing system connected to both of said devices, and

' ing devices.

alswitching system for operatively associating said'telegraphing system with said'line circuit through either oneof said distribut- 2. A telegraph system comprsing a line circuit, two rotary distributors, atransmitting means for impressing. impulses upon said line circult in accordance with a code and conname by multiple connections to said distributors, a recording means for. receiving impulses from'said line circuit" and connected by multiple connections to said distributors, and switching means for simultaneously rendering one distributor ineffective andthe other distributor eifective to associate said trans? .mitt ng and I6C1V1I1g. means with said line utors, and forassociating-said receivingdevice with the receiving segments of one or the other of said distrlbutors, and means for connecting sald loop c1rcu1t to a line.

4:. -A-telegraph station for operation in con inection with high speed signaling lines and with lowspeed signaling lines which comprises a high speed distributor and a low 'speeddistri utor each having sending and receiving contact faces, brush arms, driving andjs'peed control means for said arms, a com- I mon signal transmitterincluding storing and control relays .multipled to. corresponding contacts on said sending faces, a common signal recording devlce multipled to corresponding contacts of said receiving faces, a loop circuit connecting through said sending faces in series and including a line relay having having lines for] contacts for transfer of signalsfrom said loop circuit through saidreceiving face to said recordingd'evice, a source of electrical power, and switching means having. contacts. for

switching said source of power from one of i said driving means to the other to stop one distributor and to drive'the other and having contacts for completing the loopcircuit over a by-patharou'nd' the-sendingflface of said stoppeddistributor to prevent it from multil'ating signals in'said loop circuit and also having contacts for switching the signal transferfcontacts of said. line relay'from the receiving face of said one stoppeddis'tributor to'that of said other driven-distributon said switching V perations being reversible'in respect to said two-distributors. I i

5. A telegraph system comprlsing a plurality of lines having different signaling fre- 'qu'encies; a transmitterlhaving aplurality of selectively operated circuitfclosing devices, a plurality of distributing mechanisms for transmitting to said lines'seriesof impulses determined by the selection of said, circuit closing devices and at frequencies. corresponding to said signaling frequencies, and switching means for connecting said circuit closing devices successivelyto said lines through any one ofsaid; distributing mechanisms in accordance with the required frequency. 1

-' 6 In a telegraph signaling system including: linesfor high and jilow speed signaling, a printing telegraph set comprising a loop circuit including means for making connection'with any one of said'lines, a high speed sending distributorand a low speedfsending distributor each having: transmitting segments for opening and closing said loop circuit, common transmitting means multipled to corresponding transmitting segments. on said high and low speed distributors to cause the opening and closing of said loop circuit by either ofsaiddistributors, and switching means for bridging the segments on either of said distributors to prevent mutilation of the signals transmited-over the loop bythe other of-said distributors; I w

7. A telegraph system comprising a .pluralityof' lines for at least two different signal frequencies, a line'circuit including a line relay, means for connecting said line circuit to any one of said lines, a recorder having a plurality of selecting magnets, a plurality of dlStIlblltlIlg mechanisms for receiving. from said line relay a series of impulsesfor selection of. said magnets, and switching-means for connecting said selecting magnets successively to said lineIrelay through any one of said distributing mechanisms in accordance with the signalfrequency of the line con.-

nected to said linecircuit,

; 8 I1 1 a telegraph signaling system, aline a I station equ pment for I reception of signals qm' sald. s c mpr i g a o p circ t f r insertion in said line and including a line relay responsive to signals passing over said line, a first motor driven receiving distributor normally adjusted for isochronism with a high signaling speed on said line, a second motor driven receiving distributor normally adjusted for isochronism with a considerably lowersignaling speed than said first distributor, a signal recording device normally connected for operation from either of said distributors, a source of electrical energy, and switching means for supplying driving power from said source to said first distributor or to said second distributor and for connecting said line relay in operating relation with said first distributor or said second distributor, respectively, for reception of signals by said recording'device in accordance with the signaling speed of said line.

9. A printing telegraph system for operation with high and low speed lines, comprising a high speed signal distributing device, a, low speed signal distributing device, each device having a movable contacting element and means for arresting the movement of said element at the end of a signal, a common relay for operating said arresting means to release said contacting elements, and switching means for selectively connecting said relay to either one of said arresting means in accordance with the speed of the line with which said system is operated.

10. A printing telegraph system for operation with high and low speed lines comprising a loop circuit including connecting means to any one or" said lines, a high speed distributor having a sendlng and a receivlng 'face, a low speed distributor having a sending and a receiving face, common signal transmitting means connected by multiple connections to both of said sending faces for signaling over anyone of said lines, common signal recording means connected by multiple connections to both of said receiving faces for reception from any one of said lines, means for driving said distributors at their predetermined speeds, and switching means for conditioning said driving means for operation of either one of said distributors and for inoperation of the other of said distributors.

In witness whereof, we hereunto subscribe our names this 6th day of June, 1931.

ARTHUR E. HUNT. WILMARTH Y. LANG. 

